"I'm naked. But when I do get to wear clothes, I love the '70s outfits," Lawrence told SciFiNow.

"Some of the Mystique look is a little different, but we're still using the same paint. But she's different in this film too. She was struggling - like a lot of normal humans - with the way she looked, and she was covered up a lot in the first movie, but this time she is Mutant and proud."

X-Men: Days of Future Past will be based on Chris Claremont's acclaimed Marvel comic book storyline from the early '80s.

Director Bryan Singer's blockbuster will unite both X-Men casts, with Hugh Jackman's Wolverine sent back in time to change history.

Michael Fassbender, James McAvoy, Nicolas Hoult, Patrick Stewart, Ian McKellen, Halle Berry and Anna Paquin also return to the franchise, while Game of Thrones star Peter Dinklage will play Sentinel creator Bolivar Trask.